Apparatus for distilling liquids



Jan. 14, 1930. w. E. SANGER APPARATUS FOR DISTILLING LIQUIDS Filed July25, 1925 Patented Jan. 14,1930

UNITED STATES PATIENT OFFICE 'WALTEB E.,SANGEB, OF CHICAGO, ILLINOIS;UNION TRUST COMPANY, OF DETROIT, MICHIGAN, EXEC'UTOR OF THE SAID WALTERE. SANGER, DECEASED, ASSIGNQR TO OSCAR H. WURSTER .Applicationfiled'July 23,

This invention relates to an apparatus for distilling various liquids,and especially those which show a tendency to partially decom osedirectly or alone at normal pressure. uch liquids are distilled in apartial" Vacuum whereby the boiling point of the liquids is lowered inaccordance with the degree of exhaustion. The improved apparatus isparticularly adapted for distilling crude glycerine, but'the inventionis not limited to this particular substance.

The object of the invention is to provide an improved apparatus for.performing distillations of the nature referred to above.

The present invention may be considered in some respects as animprovement upon the invention disclosed in my prior Patent No.1,452,617, granted April 24, 1923.

' The present invention is exemplified in the combination andarrangement of parts shown in the accompanying drawingand described inthe followingspecification and in the steps of the process disclosedtherein.

In the drawing, the figure is a diagrammatic elevation, with'parts insection, showing one form of apparatus comprised in the presentinvention.

As shown in the drawing, the numeral designates a still of the samegeneral nature as shown in my prior patent referred to above. The stillis provided with an internal heating coil 11 through which steam orother heating medium may be circulated for evaporating the contents ofthe still. The still may be additionally heated by an external sourcevin the usual manner if desired. pipe 12 enters the top of the still andis provided with a perforated'spider 13 at the bottom from which heatedvapor'is discharged into the glycerine or other liquid within the stillto assist in the operation. A ring or coil 14 is positioned near thebottom of the still and is of slightly less diameter than the coil 11.The

erforations for directing fluid discharge therefrom toward the top ofthe coil 11. Outside the still the ,coil 14 is provided with connections15 and 16 by which either air'or steam may be introduced into theperforated ring 14. .At the top of the still a second perforated ring 171s described in my prior patent.

APPARATUS FOR DISTILLING LIQUIDS 1923. Serial No. 653,074.

' ber 23 and end chambers 24 and 25 separated from one another by heads26. The cham- "bers 24 and 25 are connected by a series of tubes 27passing through the central chamber 23. Baflle plates 28 are preferablyprovided for directing the vapor from the pipe 19 about the tubes 27.The tubes 27 are supplied with vapors at a lower temperature than thatof the vapor from the still in a manner to be explained so that thevapor from the still will give up a portion of its heat to the vaporpassing through the tubes and in this way a portion of the glycerinewill be condensed and pass downwardly into a receiver 29. Theuncondensed portion of the vapor from the distilling liquid will risethrough pipe 30 and pass through pipes 31 and 32 to a second condenser33. To eflfeot this operation the valve 34 will be closed and the valve35'open. The condenser 33 is of the same general construction as asuperheater condenser 21 and is provided with pipes through which acooling medium may be circulated, the medium being supplied byconnctions 36. Watermay be used as a cooling medium or oil may beemployed and the amount of condensation may be controlled by thetemperature of the cooling medium which can be regulated as desired.

The condensate from the condenser 33.

passes through pipe 39 intoa-collector 40. If further condensation is,desired the vapors may pass from the collector 40 through pipe 41 to athird condenser 42 similar to the conthe glycerine, and glycerine of anydesiredgravity may be obtained. For example, if a sufiiciently hightemperature condensing medium is used it would be possible to obtainglycerine of dynamite grade without further concentration. By the use ofsuccessive condensers with decreasing temperature of condensing mediumall of the glycerine may be condensed separately, giving varyingconcentrations of glycerol. In some cases a single condenser 33 inaddition to the superheater g condenser 21 will be sufiicient, and insuch cases the condenser 42 and its receiver 47 will be omitted.

The various receivers 29, 40 and 47 are arranged to drain into a pipe 50which is con- 58 nected by means of a pipe 51 to the bottom of aconcentrator 52. The opposite end of the ipe 50 is connected throughpipe 53 to the ttom of the evaporator 54, there being a syphon bend 55in the pipe 53 for purposes to be described. Valves 56, 57, 58 and 59control the pipe connections so that the condensate from the differentreceivers may be conducted either to the concentrator 52 or theevaporator 54. The concentrator 52 is provided with a heating coil 60which ma be supplied with steam or other heating medium from anysuitable source, and at the upper portion of the concentrator a separatecoil or coils 61 is located to which a heating medium may be supplied byconnections 62 for superheating the vapor arising from the concentrator.The glycerine in the concentrator will have a relatively high boilingpoint so that the exhaust steam from the plpe 60 may coil62 in theevaporator 54. The evaporator 54 will be supplied either with waterthrough a connection-63 or with the distillate from the-receiver 47, orperhaps from the receiver 40. This distillate which enters theevaporator throu h pipe 53 will have the larger portion 0% its glycerinecondensed therefrom and returned to the concentrator 52 through the pipe51 so'that the liquid supplied to the evaporator will have only a smallpercentage of glycerine and is known as sweet water. 7

The vapor from the evaporator 54 may be passed through pipe 65 to theupper portion of the concentrator 52 where it is subjectedto the actionof the superheating coil 61 and mingles with the vapor from theconcentrator 52. It then passes upwardly'through pipes 66 and 67 to thesuperheater condenser 21 where under ordinary operation it is further beused for supplying heating medium to the discharged into the crudeglycerine to aid in distillation in the manner described in my priorpatent.

It will be seen that the exhaust pump 49 operates through the variouscondensers in series to the top of the still 10. The upper portion ofthe evaporator 54 and concentrator 52 are connected with the bottom ofthe still so that the evaporator and concentrator will also operate at areduced pressure due to the action of the pump, but in actual prac: ticethe pressure in the evaporator and concentrator, will be greater thanthat in the still, the diflterence in pressure usually corre: spondingto a head of approximately ten inches of mercur If the still is operatedsay under 28 inc es of vacuum, the vapors from the evaporator are at atemperature of steam at approximately 18 inches of vacuum or about 173Fahrenheit.

, The .liquor in the concentrator is a highly concentrated solution ofglycerine and water with some impurities and has a boiling point ofapproximately 300 Fahrenheit and the vapors passing from theconcentrator have a temperature closely approximating this temperature.I find that these vapors from a concentrated solution of glycerine (70to 90% glycerol) will carry over mechanically.

or through partial pressure an appreciable amount of glycerol,thesevapors after concentration of the same analyzing an average of 3%of glycerine. Heretofore these 0011- densed vapors have been collectedas sweet water which yields an inferior product or were re-distilledwith the sweet water if that method of disposing of glycerine in sweetwater was resorted to. proved process these vapors are not condenseddirectly but passed to the still in the form of vapors and are used fordistilling the crude glycerine contained therein. With this arrangementmore glycerine is obtained in a purer form, such as dynamite glycerine.

I find that by providing superheating coils (through which there ispassed steam ata' temperature in excess of 360 Fahrenheit) in the upperpart of the concentrator and passin both the vapors from the evaporatoran the concentrator around these coils, that the resultant mixture ofthese vapors enters the superheater at a considerably higher temperaturethan-if the vapors of the 'sweet water evaporator are utilized andperature there is a smaller difierencein temperatu're between the vaporspassing/from the still and the injection vapors so that less glycerineis automatically condensed in the superheater, and that which iscondensed is of a higher degree of concentration.

By the use of successive condensers, as described with decreasingtemperature of condensing medium, all .of the glycerine may be condensedseparately, giving various concentrations of glycerol in the diiferentreceivers. The piping of the return lines from the various receivers isso arranged that any part of the distillate may be returned to theconcentrator or to the sweetwater evaporator, as desired. As previouslypointed out, the sweet water evaporator 54 will be un der a vacuum of;approximately 18 inches, while the sweet water receivers are morethoroughly exhausted and are under a vacuum of about 28 inches. In orderthat the sweet water will run by gravity from the receivers to theevaporator without danger of reverse flow it is necessary that there bea considerable difference in'level or head between the bottom of thereceivers and the level of the liquid in the evaporator. I find that byusing a siphon 55 in the receiver return line, as shown in the drawing,less space is required between the bottoms of the receivers and the topof the evaporator, since it is always necessary to lift a head of waterto the top of the siphon before there is danger of return flow from theevaporator to the receiver. This reduces the height necessary for theequipment, allowing it to be installed in buildings with lower ceilings.To further guard against any chance of return flow of the sweet waterfrom the evaporator through the receiver and through the exhaust pumpwhere it would be lost, a check valve 68 may be placed in the line 53 toprevent reverse flow therein. Since the same condition may exist in theconnection between ,the concentrator andthe receivers, a check valve 69is also placed in the line 51.

In the distillation of crude glycerine the coils in the still becomecoated with material known as foots which is baked on the coil,

thus interfering with the transfer of heat. This foots is readilysoluble in hot Water and .by providing a perforated pipe 17 over the topof the heating coil and of substantially the same diameter as theheating coil, hot water may be run over the heating coil from this openpipe and the coil may thus be cleaned. and kept in a high degree ofeiiiciency. The same result may be obtained by running cold waterthrough the perforated coil 17 and keeping a small amount of steamturned on on the closed coil in the still. I find further that byplacing a. perforated coil 14 inthe bottom of the still havingconnection for steam and air that a violent splashing may be obtainedand the still may be thoroughly cleaned.-.

Assuming that, for instance, dynamite glycerine is to be produced, thecrude glycerine is fed automatically into the still 10 to which externalheat is preferably supplied.

Air is now exhausted from the entire apparatus by means of the vacuumpump 49. The evaporator 54 contains water orjis lled with sweet waterfrom a previous distillation. This water is heated by the coil 62andunder the reduced pressure the sweet water in the evaporator passes outthrough pipe into i the concentrator '52 around the superheater coil 61and into the superheater condenser 21. Here it passes through the tubes27 and may be further superheated by the vapors of glycerine and steamwhich pass upwardly from the still through pipe 19 and pass around thecondenser tubes 27 Asthe sweet water vapor which passes from theevaporator is saturated steam produced in a vacuum, its

temperature is considerably below 212 Fahrenheit. The vapors passingfrom the liquid in the concentrator are produced under a vacuum, but dueto the high concentration of. glycerine therein they have a temperatureconsiderably in excess of saturated steam at the reduced pressure, andalso partly due to the fact that these vapors carry some glycerol andglycol. The vapors from the evaporator are heated by the vapors passingfrom the glycerine in the concentrator and the mixture of vapors fromthe evaporator and concentrator are both superheated by the superheatercoil 61. Accordingly there may be a difference in temperature betweenthe va ors from the still and the vapors passing rom the concentrator,and the mixed vapors from the concentrator being cooler than those fromthe still may act as a condensing medium and a part of the glycerinewill be condensed in the superheater condenser 21. The amount ofglycerine so condensed is controlled by the amount of superheating donein the concentrator.

If the vapors from the concentrator are superheated to a temperature inexcess of the temperature of the vapors from the still none "of thevapors from the still will be condensed but on the contrary the vaporsfrom the still will be superheated. If the vapors from the ture belowthe temperature of the vapors from the still, some of the vapors fromthe still will be condensed and it will thus be amount of evaporatingsurface provided in concentrator are superheated toa temperatheevaporator and concentrator and the temperature which is theremaintained. The

pors thus injected cause the hot glycerine to distill over througn thepipe19, as stated. It will be noted that ,the pipe connection12-.extends downwardly through the still from the topthereof in thearrangement shown so that the steam contained in pipe 12 may be furthersuperheated by the vapors of the distill- ,ing glycerine as they passupwardly through the still on their way through the pipe 19. The part ofthe glycerine condensed in the condenser 21 drops into the receiver 29from which it passes through pipe 51 into the con-' centrator 52. Mostof the water vapor which is carried along with glycerine vapor does notcondense in the superheater condenser, but passes along with theremaining uncondensed glycerine through pipes 30 and 32 to the condenser33. If the condenser 33 is the only additional condenser employed, thenthe remaining vapor is condensed and drops into receiver and from therepasses through the pipe connections shown either to the concentrator 52or the evaporator 54. If the additional condenser 42 is employed, theportion of the vapor not condensed in 33 is condensed in 42 andpassesthrough the receiver 47 to the pipe connection 50, and thence tothe concen trator or the sweet water? evaporator where the glycerine isfinally concentrated to a finished product.

Perforated pipes 70 and 71 are provided for injecting open steam intothe lower part of the concentrator 52 and evaporator 54, respectively.If by any cause an impurity such as trimethylene-glycol is run into theconcentrator with the glycerine, this substance may be distilled fromthe concentrated solution of the glycerine containing this impurity byinjecting open steam through the perforated pipe 70 which is locatedbelow the level of the liquor in the concentrator. The open pipe 1 inthe evaporator may be used in a similar manner. I

In the distillation of chemically pure'glycerine the process is the sameas that described for distillation of. dynamite glycerine, except thatfresh water in place of sweet water is used for generating the vapordischarged at the bottom of the still. I find that'in making a highgrade of glycerine sweet water is unsuitable because some of theimpurities of the sweet water are carried over into the still from wherethey are distilled over. and

collectpartly in the concentrator making it impossible at times tosecure a chemically pure grade to meet the requirements of the UnitedStates Pharmacopoeia. In carrying out the process with fresh water the'water is supplied to the evaporator throughout the I said still.

which is condensed is held in the receivers until completion ofdistillation when they are evaporated in any suitable vessel.

It will, of course, beobvious that my process is not limited in itsapplication to the distillation of glycerine, but that the same may beused in distilling other liquids which'are distilled by steam or watervapors, and particularly such liquids which show a tendency to decomposewhen distilled at partial or normal pressure.

It will be apparent that the superheater coil 61 could be located in theevaporator 54 instead of concentrator 52. In this case the pipe 65 wouldconnect with the concentrator at the top thereof and enter theevaporator below the superheater coil and the pipe 66 would lead thesuperheated vapors from the top of the evaporator 54 instead of from theconcentrator, as illustrated. The two de vices 52 and 54 are verysimilar in construction and operation and in fact either could be calledan evaporator or a concentrator. The terms have been applied in themanner used above merely for convenience and because the vessel 52 iscommonly supplied with a more concentrated solution of glycerine.

It should be notedvthat my invention is not limited strictl to thevarious details of the apparatus which has been particularly described,except as panying claims.

I claim I pointed out by the accom- 1. Distilling apparatus comprising astill, v

condensate of saidvapors into said evapo-. rator, means for closlngconductlng means to exclude said condensate from said evapo rat'or,means for supplying fresh water to said evaporator so that said freshwater may be vaporized therein to produce fresh water vapors, and meansfor conveying said fresh water vapors to said still comprising asuitable conduit connecting said evaporator with 2. In a distillationunit, the combination with astill of a sweet water evaporator, a sweetwater receiver above said evaporator for receiving condensed vapor fromsaid still, a conduit extending from said receiver to said evaporator,and a check valve in said conduit preventing the return of thesweetwater to said receiver.

3. In combination, a still, a condenser for vapors from said still, areceiver for the condensate from said condenser, means for exhaustingair from said receiver, a eoneen trator positioned below and having ac011 duit connection with said receiver, and a check valve in saidconduitfor preventing return flow ot'liquid from said concentrator tosaid receiver under the influence of the vacuum in said receiver.

4. In distilling apparatus, the combination with a still, of aconcentrator in the upper part of which there is a superheating coil,means for condensing vapor from said still and directing the condensateto said concentrator, means separate from said superheating coil forheating the condensate in said concentrator to dispel vapor therefrom,and a conduit opening into said concentrator above said superheatingcoil, said conduit being connected to said still to return said vapor tosaid still after it has passed said superheater.

- 5. Distilling apparatus comprising a still, a condenser connected withsaid still, a concentrator, a liquid conduit through which condensatepasses from said still to said concentrator, heating means associatedwith said concentrator, a vapor conduit connecting said concentrator andstill through which vapor may be passed to said still, and a superheaterfor said vapors located near the top of said concentrator. I

6. In a distillation unit, the combination with a still, of anevaporator, a water line connected to said evaporator, a conduitconnecting saidevaporator with said still, and

means interposed in said conduit for heating the vapor from saidevaporator before itenters said still.

7. In apparatus for distilling glycerine, the combination of a still, acondenser connected with the upper portion of the still,.an evaporatorarranged at alower level than said condenser, means for exhausting airfrom said condenser, and a pipe line connecting said condenser with saidevaporator arranged to permit gravity flow of condensate from thecondenser to the evaporator, said pipe line having therein an upwardbend constituting a siphon at the upper end adjacent the condenser, andmeans for independently heating the still and evaporator.

8. Distilling apparatus comprising a still, a series of condensersconnected with said still for condensing vapor therefrom, a concentratorhaving a conduit connecting one of said condensers for receivingcondensate therefrom, an evaporator having a conduit connecting anotherof said condensers for receiving the condensate in the form of sweet--water therefrom, and means for introducing open steam near the bottom ofsaid concentrator, and of said evaporator.

9. Distilling apparatus comprising a still, means for introducing vaporinto said still, a superheater condenser having a pair of conduitsassociated for heat exchange, one of said conduits being connected withsaid still for passing vapors'to said still, the second of said conduitsbeing connected with said still to receive the vapors therefrom, andmeans for superhfeating the vapor passing through said first-namedconduit prior to its passage through said superheater condenser.

10. In apparatus for distilling liquids, the combination of a still, acondenser connected with the upper portion of said still, an evaporatorarranged ata lower level than said condenser, means for exhausting airfrom said condenser, and a pipe line connecting said condenser with saidevaporator arranged to permit gravity flow of condensate from thecondenser to said evaporator, said pipe line having therein an upwardbend constituting a siphon, and means for heating said still andevaporator.

11. In distilling apparatus the combina-- condensers to said evaporator,said pipe linen having therein an upward bend constituting a'siphon, andmeans for heating said still and I evaporator.

12. In distilling apparatus, the combination of a still, a condenserconnected with the upper portion of sa1d still, a recelver below saidcondenser, an evaporator arranged at a lower level than said receiver,means for exhausting air from said receiver, and a-pipe line connectingsaid receiver with said evaporator arranged to permit gravity flow ofcondensate from said receiver to said evaporator, said pipe line havingtherein an upward bend constituting a siphon, and means for heating saidstill and evaporator.

In testimony whereof I have signed my name to this specification on this18th day of July, A. D. 1923.

' IVALTER E. SANGER.

